Frequency controlled resonant inverter

Claim 1

A high-frequency generator comprising: a DC voltage source; an inverter, having a plurality of switches, connected to said DC voltage source; a transformer following said inverter and connectable to a load; an LC series resonant circuit connected between an output of said inverter and said transformer, said LC series resonant circuit containing a first inductance and a capacitance connected in series; a second inductance connected in parallel with said capacitor and forming a parallel branch; first sensor means for acquiring a current in said parallel branch, said current exhibiting zero-axis crossings; second sensor means for acquiring a current in said series resonant circuit, said current exhibiting zero-axis crossings; means for identifying the zero-axis crossings of each of the current in said parallel branch and the current in said series resonant circuit, the zero-axis crossings for the respective currents exhibiting a time delay therebetween; and means for generating a control signal for switching said switches of said inverse rectifier with a switching time which is inversely proportional to said time delay.